1. Field of the Invention
This invention pertains to the telecommunications industry where data and voice signals are transmitted optically over fibers. More particularly, this invention pertains to a switch for use in a fiber optic transmission system.
2. Description of the Prior Art
In fiber optic data and voice transmission systems, signals are transmitted in a form of light over optical fibers. The prior art has developed numerous products for interfacing optical fibers. For example, such products will include optical fiber connectors and the like.
From time to time, it is desirable to decouple two optical fibers and to redirect one of the previously coupled fibers to a different optical fiber. To accomplish such a switching function, fiber optic switches have been developed.
Fiber optic switches may operate by moving fibers transversely relative to one another (e.g., U.S. Pat. No. 4,204,744). Also, there is a variety of fiber optic switches which achieves the switching operation by rotating fibers relative to one another about a common axis of rotation.
A common feature of prior art rotary fiber optic switches is the need to precisely position fibers in a circumferential spacing about the axis of rotation. For example, in U.S. Pat. No. 4,946,247, the fibers are retained within a bore axially formed through a ferrule. The fibers are disposed in a closely packed array with the fibers abutting one another as well as abutting the internal cylindrical surface of the ferrule. As a result of such construction, the central core of each of the fibers in the array is equally spaced from one another as well as being held in a fixed spacing from the axis of rotation of the fiber. Accordingly, by rotating one of the fiber arrays relative to the other by an angular displacement equal to the angular displacement of the fibers within the array, optic coupling between opposing fibers is maintained. If, for any reason, any of the fibers were to be unevenly circumferentially spaced about the axis of rotation, transmission losses would occur since opposing fibers and would not be in accurate axial alignment.
U.S. Pat. No. 4,204,744 teaches an alternative means for maintaining fibers in a precise circumferential array. In U.S. Pat. No. 4,204,744, optical fibers are positioned on the external cylindrical surface of a rod. Spacing rods are provided on the external surface in closely abutting relation. The optical fibers are retained within the interstitial spaces defined between the supporting rods and the central rod.
As mentioned, in the prior art rotary fiber optic switches, precisely controlled circumferential spacing is necessary in order to ensure precise axially alignment of opposing fibers of the switch. If such precise axial alignment is not attained, undesirable transmission losses occur. However, controlling precise circumferential spacing can be costly and difficult to achieve. It is an object of the present invention to provide a rotary fiber optic switch which does not rely upon precise circumferential spacing of fibers.